It is conventional practice that brass or steel arming wires have provided a mechanical barrier to prevent arming or premature operation of ordnance devices. Generally, arming wires are attached to a fixed point on an aircraft such that upon release of the ordnance, arming wires are extracted from the ordnance, thereby beginning the arming sequence. Several disadvantages are associated with the use of arming wires for ordnance delivered by aircraft.
Installation procedure is complex and must be performed exactly to insure that arming wires are tied off and attached to the ejection rack in the proper locations in order to arm the ordnance as intended. The installation of one to five arming wires for each weapon is labor intensive and conducive to errors.
Through the use of a selectable arming solenoid, the pilot can control whether the arming wire is retained in the solenoid thus arming the ordnance or, released, and thus preventing the arming of the ordnance. These solenoids have a history of unreliable operation which may result in the weapon not functioning as desired.
Defective arming wires may cause improper arming by breaking prior to extraction from the ordnance device and may cause aircraft damage by remaining attached to the ejection rack after weapon release. Whipping of the broken arming wire by the airstream against the aircraft, may result in damage to composite materials or paint removal thus necessitating additional maintenance actions. Fahnestock or safety clips, installed to prevent the pulling of certain arming wires by the airstream become airborne debris once the arming wire is pulled. This debris may damage the aircraft.